Process of making indoxyl, &amp;c.



UNITED STATES I Patented May 31, 1904.

PATENT OF ICE,

CHEMICAL WORKS, OF BASLE, SWITZERLAND.

PROCESS OF MAKING IND OXYL, 600.

SPECIFICATION forming part of Letters Patent No. 761,440, dated May 31, 1904.

Application filed. March 9, 1904. Serial No. 197,342. (N specimens.)

To all whom, it m/n/y concern.-

Be it known that I, AUGUSTUS Brsonnnn,

doctor of philosophy and chemist, a subject of the Emperor of Russia, and a resident of Basie,

Switzerland, have invented new and useful Improvements in the Manufacture of Indoxyl, its Homologues, and their Derivatives, of

which the following is a clear and complete glycin salt, caustic-alkali, and sodium alcoholate; but the yield of indigo is much too small to think of making any technical use of this proceeding. I

I have found that a much better yield of indoxyl is obtained by not employing simply sodium alcoholate for the condensation of thephenylglycin salt to indoxyl, but a product obtained by dissolving sodium in an equivalent quantity of an alcoholic solution of caustic potassium hydroxid (caustic potash) and distilling 01f the alcohol in cacao. The condensing effect of such a product is further in-. creased by an addition of metallic sodium and eventually of small quantities of some slightlyreducing substances, such as sodium sulfite. The small quantities of sulfite probablyv have a conserving influence on the alcoholate, thus increasing its efficiency.

' Example I: 6.9 parts of sodium are dissolved in asolution of seventeen parts of welldried caustic potash in one hundred and fifty parts alcohol of one hundred per cent. This solution is mixed with 0.5 parts sodium sulfite and the excess of alcohol completely distilled off in anoil-bath by employing vacuum toward the end of the operation. To the yet hot mixture thus obtained are added forty parts caustic potash and twenty parts sodium salt of phenylglycin, and the mixture is heated to 220 centigrade whilestirring. Then one part sodium and 0.5 parts sodium sulfite are still added, and the whole is melted down for about one hour at a temperature of 240 to 250 centigrade. The thus-obtained indoxyl is transformed into indigo in the usual manglycid, alph'a-phenylhydantoins, &c., thus forming indoxyl or homologues of indoxyl.

Example II: The yet hot reaction product of sodium on alcoholic caustic potash produced according to example I, but without ad- .dition, of sodium sulfite, is mixed with fifty parts caustic potash and twenty-five parts phenylglycin-anilid heated to 220 centigrade, and then three parts of sodium are added. This mixture is melted down for about one hour at 250 to 260 centigrade, (until tests successively taken from this mass show no more increase of indigo.) The anilin vapors are conducted to a cooling appara- The reaction product tus, (condenser.) The reaction product is worked up to indigo in the habitual manner.

What I claim is 1-. The described process for the manufac ture of indoxyl, its homologues and their derivatives by melting alkali salts and other compounds of the arylglycins and of their derivatives with caustic alkalies, metallic sodium and a reaction product of sodium'on alcoholic caustic potash, obtained by dissolving sodium in an alcoholic solution of caustic potash and distilling off the alcohol.

2. The described process for the manufacture of indoxyl, its homologues and their derivatives by melting alkali salts and other compounds of the arylglyoins and of their derivatives with caustic alkalies. metallic sodium, a small quantity of a slightly-reducing substance and a reaction product of sodium on alcoholic caustic potash, obtained by dissolving sodium in an alcoholic solution of caustic potash and distilling off the alcohol.

3. The described process for the manufac- In witness whereof I have hereunto signed my name, this 26th day of February. 1904, in IQ the presence 0t two subscribing Witnesses.

AUGUSTUS BISCHLER.

Vi tnesses: V

GEO. GIFFORD, AMAND BITTER. 

